Women using oral contraceptives were found to have significantly lower serum magnesium levels in a controlled study.4 In a preliminary study, blood levels of magnesium decreased in women taking an oral contraceptive containing ethinyl estradiol and levonorgestrel.5 Although the importance of this interaction remains somewhat unclear, supplementation with 250 to 350 mg of magnesium per day is a safe and reasonable supplemental level for most adults.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.6, 7, 8 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.9 Oral contraceptives may interfere with manganese absorption.10 The clinical importance of these actions remains unclear.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.11, 12, 13 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.14, 15 Oral contraceptives may interfere with manganese absorption.16 The clinical importance of these actions remains unclear.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.17, 18, 19 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.20, 21 Oral contraceptives may interfere with manganese absorption.22 The clinical importance of these actions remains unclear.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.23, 24, 25 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.26 Oral contraceptives may interfere with manganese absorption.27 The clinical importance of these actions remains unclear.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.28, 29, 30 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.31, 32 Oral contraceptives may interfere with manganese absorption.33 The clinical importance of these actions remains unclear.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.34, 35, 36 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.37 Oral contraceptives may interfere with manganese absorption.38 The clinical importance of these actions remains unclear.

Reduce Side Effects

In a double-blind trial of oral contraceptive users with cervical dysplasia, supplementation with very large amounts (10 mg per day) of folic acid improved cervical health.39 Women with cervical dysplasia diagnosed while they are taking oral contraceptives should consult a doctor. Mega-folate supplementation should not be attempted without a doctor's supervision, nor is there any reason to believe that folic acid supplementation would help people with cervical cancer.

In a double-blind trial, supplementation with 20 mg of vitamin B6 twice a day for 2 months improved depression in women taking oral contraceptives who had laboratory evidence of vitamin B6 deficiency.40 However, vitamin B6 did not relieve depression in women who did not have vitamin B6 deficiency.41

Support Medicine

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.42, 43, 44 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.45, 46, 47 Oral contraceptives may interfere with manganese absorption.48 The clinical importance of these actions remains unclear.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.49, 50, 51 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.52, 53, 54 Oral contraceptives may interfere with manganese absorption.55 The clinical importance of these actions remains unclear.

Reduces Effectiveness

none

Potential Negative Interaction

Eight cases reported to the Medical Products Agency of Sweden suggest that St. John's wort may interact with oral contraceptives and cause intramenstrual bleeding and/or changes in menstrual bleeding.56 One reviewer has suggested that St. John's wort may reduce serum levels of estradiol.57 It should be noted, however, that only three of the eight Swedish women returned to normal menstrual cycles after stopping St. John's wort. Women taking oral contraceptives for birth control should consult with their doctor before taking St. John's wort.

Explanation Required

Menstrual blood loss is typically reduced with use of oral contraceptives. This can lead to increased iron stores and, presumably, a decreased need for iron in premenopausal women.58 Premenopausal women taking oral contraceptives should have their iron levels monitored and talk with their prescribing doctor before using iron-containing supplements.

A review of literature suggests that women who use oral contraceptives may experience decreased vitamin B1, B2, B3, B12, C, and zinc levels.59, 60, 61 Oral contraceptive use has been associated with increased absorption of calcium and copper and with increased blood levels of copper and vitamin A.62, 63, 64 Oral contraceptives may interfere with manganese absorption.65 The clinical importance of these actions remains unclear.

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers' package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.

Please read the disclaimer about the limitations of the information provided here. Do NOT rely solely on the information in this article. The Aisle7 knowledgebase does not contain every possible interaction.

The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2016.

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